Voters will decide Tuesday which two candidates will face off in June for the chance to represent Massachusetts in the U.S. Senate.

Voters will decide Tuesday which two candidates will face off in June for the chance to represent Massachusetts in the U.S. Senate.

Democratic candidate and U.S. Rep. Stephen Lynch cancelled most campaign events Monday due to illness. His spokesman said an evening rally in South Boston would still take place.

A statewide poll released last week by the Western New England University Polling Institute shows Lynch trailing fellow U.S. Rep. Ed Markey by 10 percentage points, 44 percent to 34 percent, for the Democratic nomination.

The same survey showed both Democrats with strong leads over each of the Republican candidates in hypothetical head-to-head match-ups.

Businessman and former Navy SEAL Gabriel Gomez, former U.S. Attorney Michael Sullivan, and former state Rep. and judge Dan Winslow are battling for the GOP nomination.

A Suffolk University/WHDH-TV poll released Sunday showed Boston voters evenly split between Gomez and Sullivan, with Winslow a distant third. In Shrewsbury, also selected by the pollsters as a "bellwether" community (where local voting has mirrored past statewide results), Gomez outpaced his challengers with 48 percent support, compared with 24 percent for Sullivan and 14 percent for Winslow.

The Suffolk poll showed Markey defeating Lynch in all three Democratic bellwethers: Sandwich, Swampscott and Newburyport.

All the candidates put their campaigns on hold in the immediate aftermath of the Boston Marathon bombings, which may further decrease voter turnout. Prior to the attacks, state officials estimated that less than 20 percent of eligible voters would cast ballots on Tuesday.

"Whatever momentum this primary had — and it didn’t have a lot — was totally exhausted by the bombing," Massachusetts Secretary of State William Galvin told the Associated Press.

The attacks have turned into a campaign issue, with the candidates arguing over whether the bombings could have been prevented and how suspect Dzhokhar Tsarnaev should be prosecuted.

The Senate special election was triggered by John Kerry's resignation in January to become U.S. Secretary of State. Gov. Deval Patrick appointed William "Mo" Coawan to fill the seat on an interim basis.